1. Field of the Invention
The present invention relates to a method of fabricating an organic light emitting diode display device, and more particularly, to a method of fabricating an organic light emitting diode display device capable of simplifying a manufacturing process. Furthermore, it relates to a diode display device.
2. Discussion of the Related Art
For an image display device which embodies a variety of information on a screen as a core technology in advanced information and communication, there is continuous progress in development of slim, lightweight, and portable devices with improved performance. Hereupon, organic light emitting diode display devices that display an image by adjusting an amount of light emitted from an organic light emitting layer are recently receiving attention as flat panel display devices having reduced weight and volume, which are drawbacks of cathode ray tubes (CRTs).
An organic light emitting diode display device applies an electric field to an anode and a cathode formed at both ends of an organic light emitting layer so as to inject and transfer electrons and holes into the organic light emitting layer, thereby utilizing an electroluminescence phenomenon in which light energy is released through recombination of the electrons and holes. The electrons and holes, which are paired with each other in the organic light emitting layer, emit light when falling from an excited state to a ground state.
Organic light emitting diode display devices have a slim design and operate at a lower driving voltage, e.g., at about 10 V or less, than plasma display panels (PDPs) or inorganic electroluminescent (EL) displays, thereby consuming less power. Much attention has been paid to organic light emitting diode display devices due to excellent characteristics thereof in terms of weight and color.
Hereinafter, a conventional organic light emitting diode display device will be described with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view illustrating a conventional organic light emitting diode display device.
Referring to FIG. 1, a conventional organic light emitting diode display device includes a substrate 10 in which a display region and a non-display region are defined and a plurality of organic light emitting cells formed in the display region of the substrate 10. Each of the organic light emitting cells includes an anode 20 connected to a transistor (not shown) formed on the substrate 10, a hole common layer 30a, an organic light emitting layer 40, an electron common layer 30b, and a cathode 60.
When the organic light emitting cell applies a voltage to the anode 10 and the cathode 60 via a pad region (not shown) formed in the non-display region of the substrate 10, holes from the anode 20 and electrons from the cathode 60 are injected into the organic light emitting layer 40. Then, the holes and electrons injected into the organic light emitting layer 40 recombine to create excitons that emit light when falling from an excited state to a ground state.
Meanwhile, as organic light emitting diode display devices are increased in display area, resistance of the cathode 60 increases. In particular, since the cathode 60 is formed of a transparent metal in a top emission type organic light emitting diode display device in which light emitted from the organic light emitting layer is transmitted through the substrate 100, resistance of the cathode 60 further increases. Thus, in a conventional organic light emitting diode display device, resistance of the cathode 60 may be reduced by forming a metal pattern 20a using a low resistance metal and connecting the metal pattern 20 with the cathode 60.
However, the metal pattern 20a formed in the same layer as the anode 10, the organic light emitting layer 40, the hole common layer 30a, and the electron common layer 30b should be formed using a shadow mask such that the organic light emitting layer 40, the hole common layer 30a, and the electron common layer 30b are only formed on a portion of the anode 20 exposed by a bank 50 formed to define the luminescent region of a sub pixel. Thus, a complex process and a high cost are required to fabricate conventional organic light emitting diode display devices.